Jessica Ennis-Hill will make her long-awaited major championship comeback in the Bird's Nest stadium on Saturday, seven years after missing the Beijing Olympics with a career-threatening injury.
The 29-year-old will go head to head with Katarina Johnson-Thompson, for the first time since her team-mate emerged as a genuine rival to her heptathlon crown over the first two days of the World Championships in the Chinese capital.
The Sheffield athlete missed out in 2008 due to a stress fracture in her right foot, only to bounce back in style by storming to the world title the following year.
This time her break from the track has been for happier reasons - the birth of her son Reggie last July.
"Having that disappointment in 2008 I knew that I didn't want to be that athlete who gets an awful injury and you never hear of her again," said Ennis-Hill, who watched the heptathlon competition on television at home alongside coach Toni Minichiello, her foot in a protective boot
"I knew that I wanted to come back and do everything I possibly could to make sure I was that same athlete, if not better. But I could never imagine I would go on to win what I won in the following years and be in the situation I am now."
Olympic glory in London when the poster girl of the Games was an achievement scarcely to be topped, but her progress since returning to competition in May has been rapid and raised hopes of a successful title defence in Rio next year.
In the short term, the three season's bests she set over the 100 metres hurdles, 200m and long jump at the Anniversary Games in London at the end of July have indicated an immediate return to the podium is on the cards.
Although an "added bonus" in a comeback season, Ennis-Hill is at these World Championships with the sole intention of winning a medal.
"I'm really ambitious and I'm competitive and I want to do my best," she said.
"I'm here halfway round the world, away from my son for over two weeks and I want to make it worthwhile and perform well."
For 22-year-old Johnson-Thompson, the Beijing Games were the first she watched, aged 15.
At London 2012 as a 19-year-old she admitted she was too nervous to speak to Ennis-Hill during competition.
"I didn't want to talk to her in case I got in the way of her focus," she said.
The Liverpool athlete admitted she was "really scared" when tipped by Ennis-Hill three years ago to be the athlete to beat in Rio.
"I remember thinking how far behind I was and how advanced these girls were and how I was never going to progress that much in four years," she said.
"I started to stress a little bit after that so I am thankful I have been able to progress as fast as I have and it's all come together for me."
That progress has included breaking her team-mate's British record to win pentathlon gold at the European Indoor Championships in Prague in March, but she knows this weekend's competition is a step up.
"For me this is probably the biggest thing I am ever going to do," added Johnson-Thompson, who will also compete in the long jump in Beijing.
She has not done a heptathlon for 15 months due to injury, struggling with a knee problem after Prague and then a quad issue in July.
But she reckons she is 95 per cent back to her best, with only competition practice now lacking.
"I feel I've been training non-stop to get to this place so finally I am in some sort of shape and feel ready to compete," added Johnson-Thompson, who predicted around 6,700 points would be needed to get a medal, 6,800 for the gold.